Air purifier



FIG. 1 is a perspective view of the air purifier showing our new design;

FIG. 2 is a front view thereof.

FIG. 3 is a rear view thereof.

FIG. 4 is a left side view thereof.

FIG. 5 is a right side view thereof.

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

Some of the solid lines in the figures are radius-transition lines that demarcate where a surface's curvature transitions from one radius to another. Such radius-transition lines would not appear as visible lines to an observer of the air purifier. 

CLAIM The ornamental design for an air purifier, as shown and described. 